Hyperbolic Metamaterials Approaching Reality

Metamaterials are a class of materials with literally unnatural properties and could have a great impact on technology. Incorporating them into modern technology is proving difficult though, as producing them can be very difficult, especially if you want them small enough to fit within certain devices. Researchers at Purdue University and Brookhaven National Laboratory however have found a way to fabricate special superlattices which could lead to hyperbolic metamaterials.

Metamaterials are an interesting consequence of physical laws being mathematical, as the equations can be manipulated by man in ways Nature cannot achieve. Hyperbolic metamaterials specifically behave like a metal when light strikes them in one direction and an insulator when the light comes in at perpendicular to that direction. This extreme change results in hyperbolic dispersion, and that allows more photons to be extracted than normally possible. Creating these metamaterials is very difficult though as they require very precise manufacturing techniques, and typically the materials being worked with are incompatible with current CMOS processes. What the researchers found is a way to create superlattices using epitaxy with titanium nitride and aluminum scandium nitride. Epitaxy works by actually growing the desired crystals and this is one of the first times it has been used to grow crystals made of both metals and insulators with atomic-scale precision.

As it is now, the researchers have not yet created hyperbolic metamaterials using this epitaxy technique, but building the superlattices is an important step to that end. Once that is achieved then we could see these ultra-thin crystalline films applied to improve solar collectors, sensors, optical microscopes by a factor of ten, and even quantum computers.